Implement most of the chunk format

src/World/Chunk.cpp

@@ -0,0 +1,101 @@
+/*
+  Copyright (c) 2015, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include "Chunk.hpp"
+
+#include <iostream>
+#include <stdexcept>
+#include <cstdlib>
+
+#include <zlib.h>
+
+
+namespace MinedMap {
+namespace World {
+
+std::tuple<UniqueCPtr<uint8_t[]>, size_t> Chunk::inflateChunk(uint8_t *data, size_t len) {
+	size_t outlen = 0;
+	uint8_t *output = nullptr;
+
+	z_stream stream = {};
+	int ret = inflateInit(&stream);
+	if (ret != Z_OK)
+		throw std::runtime_error("inflateInit() failed");
+
+	stream.next_in = data;
+	stream.avail_in = len;
+
+	while (stream.avail_in) {
+		outlen += 65536;
+		output = static_cast<uint8_t *>(std::realloc(output, outlen));
+
+		stream.next_out = output + stream.total_out;
+		stream.avail_out = outlen - stream.total_out;
+
+		ret = inflate(&stream, Z_NO_FLUSH);
+		switch (ret) {
+		case Z_NEED_DICT:
+		case Z_DATA_ERROR:
+		case Z_MEM_ERROR:
+			inflateEnd(&stream);
+			throw std::runtime_error("inflate() failed");
+		}
+	}
+
+	inflateEnd(&stream);
+
+	return std::make_tuple(UniqueCPtr<uint8_t[]>(output), stream.total_out);
+}
+
+Chunk::Chunk(uint8_t *buffer, size_t buflen) {
+	if (buflen < 5)
+		throw std::invalid_argument("short chunk");
+
+	size_t size = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
+	if (size < 1 || size > (buflen - 4))
+		throw std::invalid_argument("invalid chunk size");
+
+	uint8_t format = buffer[4];
+	if (format != 2)
+		throw std::invalid_argument("unknown chunk format");
+
+	UniqueCPtr<uint8_t[]> data;
+	size_t len;
+	std::tie(data, len) = inflateChunk(buffer+5, size-1);
+
+	std::cerr << "Chunk has size " << size << " (" << len << " inflated)" << std::endl;
+
+	Buffer nbt(data.get(), len);
+
+	std::pair<std::string, std::shared_ptr<NBT::Tag>> tag = NBT::Tag::readNamedTag(&nbt);
+	if (tag.first != "")
+		throw std::invalid_argument("non-empty root tag");
+
+	content = std::move(tag.second);
+}
+
+}
+}